| County | Reported* | Tested | Positive | % Tested Positive |
| Alameda | 558 | 7 | 6 | 86% |
| Alpine | - | - | - | - |
| Amador | 2 | - | - | - |
| Butte | 61 | 13 | - | - |
| Calaveras | 8 | - | - | - |
| Colusa | 13 | 4 | 1 | 25% |
| Contra Costa | 511 | 53 | 3 | 6% |
| Del Norte | - | - | - | - |
| El Dorado | 71 | 17 | - | - |
| Fresno | 157 | 17 | 11 | 65% |
| Glenn | 7 | - | - | - |
| Humboldt | 17 | - | - | - |
| Imperial | 3 | - | - | - |
| Inyo | 1 | - | - | - |
| Kern | 43 | 4 | 1 | 25% |
| Kings | 17 | - | - | - |
| Lake | 20 | 10 | 1 | 10% |
| Lassen | 1 | - | - | - |
| Los Angeles | 776 | 98 | 5 | 5% |
| Madera | 16 | 3 | - | - |
| Marin | 87 | 4 | - | - |
| Mariposa | 1 | - | - | - |
| Mendocino | 15 | - | - | - |
| Merced | 44 | 4 | 1 | 25% |
| Modoc | - | - | - | - |
| Mono | 1 | - | - | - |
| Monterey | 38 | 5 | - | - |
| Napa | 30 | 6 | - | - |
| Nevada | 31 | 4 | - | - |
| Orange | 437 | 157 | 4 | 3% |
| Placer | 227 | 83 | 8 | 10% |
| Plumas | 3 | - | - | - |
| Riverside | 174 | 48 | - | - |
| Sacramento | 795 | 298 | 27 | 9% |
| San Benito | 4 | 1 | - | - |
| San Bernardino | 137 | 31 | - | - |
| San Diego | 463 | 172 | 33 | 19% |
| San Francisco | 103 | 13 | - | - |
| San Joaquin | 213 | 49 | 7 | 14% |
| San Luis Obispo | 62 | 11 | - | - |
| San Mateo | 570 | 165 | - | - |
| Santa Barbara | 50 | 18 | - | - |
| Santa Clara | 796 | 172 | 26 | 15% |
| Santa Cruz | 104 | 30 | - | - |
| Shasta | 17 | 6 | - | - |
| Sierra | 1 | - | - | - |
| Siskiyou | 3 | - | - | - |
| Solano | 150 | 33 | 3 | 9% |
| Sonoma | 155 | 16 | 1 | 6% |
| Stanislaus | 160 | 13 | 1 | 8% |
| Sutter | 26 | 8 | 1 | 13% |
| Tehama | 14 | - | - | - |
| Trinity | - | - | - | - |
| Tulare | 73 | 20 | 8 | 40% |
| Tuolumne | 5 | - | - | - |
| Ventura | 132 | 22 | 1 | 5% |
| Yolo | 219 | 47 | 5 | 11% |
| Yuba | 29 | 7 | - | - |
| State Totals | 7651 | 1669 | 154 | 9% |
* Birds in a die-off are not included in reported totals because the deaths are not related to WNV. A die-off is defined as a group of 10 or more same species dead birds unless the species is American Crow.
Source: Vector-Borne Disease Section, California Department of Public Health